Glass transition with decreasing correlation length during cooling of Fe 50 Co 50 superlattice and strong liquids
Glass transition with decreasing correlation length during cooling of Fe 50 Co 50 superlattice and strong liquids
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DOI：
10.1038/nphys1823
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发表时间：
2010-02
期刊：
影响因子：
19.6
通讯作者：
Shuai Wei;Isabella Gallino;R. Busch;C. Angell
中科院分区：
文献类型：
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作者：
Shuai Wei;Isabella Gallino;R. Busch;C. Angell
玻璃化转变通常被理解为在液体冷却期间发生的结构停滞，在其结晶之前捕获系统。它适用于所有液体类别，包括金属。理论上的兴趣主要集中在“脆弱”液体过冷过程中遇到的动力学不均匀性。许多人认为，减速是由于增加动力学相关长度。在这里，我们报告的动力学和热力学的逮捕在一个系统中的障碍，而在其基态，表现出一个大的热容变化（Δ Cp = Cp，移动的-Cp，逮捕）逮捕，但显然是由一个静态的相关长度，减少时，接近转变温度Tg从上面的特点。我们表明，我们的系统，Fe50Co50超晶格，动力学模拟一个理想的“强”液体的临界点。引入液体临界点模拟，然后我们可以认为，强液体不同于脆弱的液体，通过占据一个潜在的有序无序过渡，这可以是连续的，临界的或弱的第一顺序的相对侧翼。
The glass transition is usually understood as a structural arrest that occurs during the cooling of liquids, trapping the system before it can crystallize. It occurs for all liquid classes, including metals. Theoretical interest has focused on the dynamical heterogeneity encountered during supercooling of ‘fragile’ liquids. Many suggest that the slow-down is caused by increasing dynamical correlation lengths. Here we report kinetics and thermodynamics of arrest in a system that disorders while in its ground state, exhibits a large heat capacity change (ΔCp=Cp,mobile−Cp,arrested) on arrest, yet clearly is characterized by a static correlation length that decreases when approaching the transition temperatureTgfrom above. We show that our system, the Fe50Co50superlattice, kinetically mimics an ideal ‘strong’ liquid with a critical point. Introducing liquid critical-point simulations, we can then argue that strong liquids differ from fragile liquids by occupying opposite flanks of an underlying order–disorder transition, which can be continuous, critical or weakly first order.